Transformer tank bracing



June 14, 1960 K. P. WIEDERKEHR 2941171 TRANSFORMER TANK BRACING Filed July 5, 1957 United States Patent O TRANSFORMER TANK BRACING Karl P. Wiederkehr, Elm'Grovte, Wls. asslgnor to Allia- Chxlmers Manufacturing Company, Milwaukee, Wls.

Filet! July 5, 1957, Sex. N0. 670,313

8 Claims. (C1. 336-92) 'Ihis invention rclates in general to transformer tanks. Max-e specifically this invention relates to an improved bracing for a transformer tank.

Transformer tanks must withstand a variety of internal and external pressures. During assembly the tank is placed under vacuum for .oil filling and later the oil is pressurized 10 test the tank for leaks. 'Ihe 011 is drained for shipping and the transformer is refilled under vacuum in the field. Although some transformers operate at atmospheric pressure, others are sealed and the pressure in the tank varies as the volume of the oil in the tank changes with heating and cooling.

When the changes in the oil volume would cause ex: cessive pressure variations in a closed systenx, a relief device in combination with a supply of compressed gas is provided to limit -the pressure variation.

The walls of a transformer tank are often braced by ribs to withstand the pressure variations. On. the lang flat sides of a three phase transformer, the bracing required to provide the tank with the rigidity to withstand the pressure variations may be very heavy. If wall to wall bracing were used inside the tank, the overall bracing required could be reduced. However, it is usually ve ry difficult and impractical to assemble wall to wall bracing inside the tank. 1

In one method of transformer construction, the coil assemblies are mounted on a common horizontal axis and a yoke surrounds the coil assembly in a vertical plane. When the core and coil assembly has been completed it is lowered into the tank. A pair of notched platcs at each end of the core cooperate with vertical rails inside the tank to guide the core and coil assembly into the tank and to position it. However, the coil assembly is nearly in contact with the sides of the tank, and central locations for internal bracing are inaccessible after the coil and core assembly has been placed in the tank. In some transformers of this construction braces are positioned between the Walls of =the transformer tank above the core. However, this support is inefficient because the braces are not centrally located with respect to the tank wall and interfere with the electrical connections at the top of the transformer.

In thls invention plates are attached to core clamps positioned beween the coils of the transfonner and flanged bars are mounted on the tank wall for receiving the plates. The plates interlock with tl1e flanges on the bars when the coil assembly is placed inside the tank. The plates and the bars cooperate to brace the tank walls against internal pressure and the outer faces of the plates brace the Walls against external pressure. Since it is only necessary to restrict the wall movement to within the elastic limits of the wall material, the transformer wall bracing of this invention can be made and installed within the usnal manufacturing tolerances.

Therefore it is an object of this invention to provide a new and ir'nproved bracing for the walls cf a transformer tank.

Other objects and advantages will be apparcnt from the following description when read in connection with tho following drawings in which:

Fig. 1 is a plan view of a three phase transformer with the top cover of the transformer tank' removed;

Fig. 2 is a section taken along line IIII cf Fig. l; and

Fig. 3 is an enlarged view of the interlocking platz and Substantially parallel with the tank wall 27.

bar of the tank bracing.

The transformer tank bracing of this invention is shown in Fig. 1 in connection with a threc hase transformcr 10 having th ree axially spaced cylindrical coil assemblies 11 which are mounted in the windows 12 of a rectangular core 13. The core 13 is clamped at either and between pairs of oppositely facing end frames 16 which are counected by bolts 17 passing under and over the core 13. Similar pairs of frames 18 clamp the core 13 intermediate the coil assemblies 11 by means of connecting bolts 17. The coil assemblies 11 are clamped between oppositely facing clamping plates 21 and 21a. 'I'he coil clamping plates 21 and 21a may be mounted on the transformer in any suitable way but preferably as shown, the plates 21 clamping the two outer coil assemblies are attached to the end frames 16 and the intermediate frames 18. The

center coil assembly is clamped between floating clampingplates 21a which are pressed against center coil assernbly the adjaqent outer coil assembly. The core and coil assemblies are positioned within the transformer tank 23:

The transformer tank wall brace 25 cf this inveantion comprises an arm 26 extending from the intermediate framesl8 toward the wall 27 of the transformer tank 23, a plate 28 attached to the outer end of the arm, and a flanged bar 29 atta :hed 10 the tank wall. Preferably a plurality of such braces are used with each transformer.-

The arm 28 1's attached at its inner end to, an intermedia te frame 18. and may be supported along one side by the fixed coil clamping plate 21. Any suitable supporting structure may be used for 1he 18 to position the plates near the horizontal center line 30 of the tank 23. Since the transformer tank 23 extends above the core and the coils, the arms are positioned above the center line of the coils. This position is desirable also because the arm is clear of the jacking bolts 22 which are located toward the center line of the coils.

The flat side of the plate 28 attached to the arm 26 is An edge or portion 32 of the plate preferably extends below the arm for engaging the bar 29. If desired, additional support for the plate 28 may be provided such as tl1e support 33 positioned between the arm and the upper part of the plate.

The flanged bar 29 is mounted on he tank wall 27 in any suitable way such as by welding. The flanged portion 35 cf the bar 29 is removed from the tank wall 27 and extends in an upward direction. The flanged portion cooperates with the wall 27 to form a groove 36 for receiving the portion 32 of the plate 28 that extends below the arm 26.

In assembly it is preferable to mount the arm 25 and the plate 28 on the clamping frames 18 before clamping the frames on the core. However, the arm and plate may be assembled at any t1'me before the coil and cores are placed in the tank. The flanged bar 29 is mounted on the tank wall 27 during the assembly of the transformer tank. When the coil and core assembly is lowered into the tank, the lower portion 32 of the plate 28 enters the channel 36 formed by the flange of the bar and the tank wall. The plates 28 are held rigid by arms which are connected by the intermediate frames, the frame connecting bolts and the intervening core matcrial.

arm but an angle iron x's illustrated. The arrns 26 are located '011 the fra'mes In operation the upward projecting flange 35 of the bar 29 and the downward projecting portion 32 of the plate 28 cooperate -to limit tlie outward movement of the tank Walls causedby internal pressure. Whenthatank is: under vacuurh, the plates 28 ahnt the tankwalls to limft thg: inwarclmovementof tha alls.

Although but one emhodiment cf bis invention has been illustrated, it willbe apparent.to those. skilled in;the arL that variationa are possible within the scopa oi the appended claims.

What is claimed is:

1.. A wall btace for iransformer tanlrs comprising an transformer tankand theedge cf said plate extending be- 1ow said. arm and a bar mountecl on said wall, said. bar having a flange removed from. said wall to forma groove forreceiving said edge cf said plate.

3-. A. wall brace for transformer tanks comprising an arm moumed ca thacore frame of the transfrner, a

platamounted 011 tha freefend of. said arm, said plata heing; positionable adjacent a wall of tha transformar tank kandhaving a portion extending below said arm, and a. bar mounted on saidwall, said bar having aflange removedfrom.saidwall to forma g roove for veceivi'ng said plate.

4. A wall brace for transformer tanks comprising an arm. mounted 011 the core. frame cf the transformer, a

platt: rimunted on the free and of said arm, said plate being Substantially parallel to a wall of the transformer tank and having aportion extending below said arm and a bar mounted on. said.wall, said bar having a flange removed from said.wall to form a groovefor receiving said plate portion below said 5. A wall brace for transformer tanks comprising an arm m'ounted on the core frame of the transformer and extending outward toward afwall of the tank, a plate mounted on the free end of said arm and positionable near the horizontal center line, said plate being substantially parallel to said wall and having a portion extending beloWsaid arm, and a barmounted 011 said wall, said bar having a flange removed from said wall to form a groove for recerving said plate extensibn;

6. A wall b race fort transformertanks comprising: arms;

mounted:- on .the cora fra-mes of. the.trausformcr, a.-plate mounted on the free' end of each of said arms, said plates being substantiallV parallel .to the W311S*0f'11h6 transformer tank, and bars mounted on said walls and positionable adjacent said plates, said bars having a flange removed from said walls to form grooves for receiving said plates.

7. A transformer comprising a core and coil assemblies spaced alongsaid" core, said traflsformer being positi'oned wi'thirra tank, core frames positioned intermediate said coil assemblies for clamping said core; arms mountecl on said framesand extendingoutwardly toward thewalls of aiditank, plates mountecl on the frae and of said arms and barsmounted on said walls and positioned adjaoe'nt said plates, saidbars havin'g a flanged portion spacecl from said Walls to define grooves for receiving said plates.

8. A transf0rmer comprising a core and coil assembl'ies spaced along said core, said transformer boingp0sirionedwithin a tank, core frar nes 'positioned intermediata said coil assemblies for clamping said core arms mounted on said framea and exteriding; outwardly toward the walls ofi. said; tank plates mounted on the freeend. cf said arms,

1 said plates beir1g,substantially parallel tosaid Walls and positioned nearwthe horizontal center 1ine o-frsaid"tank and bars mounted on said Wallsand posi.tioned adjacent said: plates, said bars haviflg a flanged portion spaced from said Walls to defme grooves forreceiving said plates.

References Cited in the filaof this: patent UNITED STATES' PATENTS 2.822,527 Jerry Feb. 4,1951; 

